Influence of the dipole-dipole interaction on the interference between Bose-Einstein condensates

We have investigated the interference of the dipolar Bose-Einstein condensates (DBECs) released from a double-well potential and studied the effects of dipole-dipole interaction (DDI) on the interference phenomena. We find that the DDI plays an important role in the interference process. When the effective polarization direction of the dipolar atoms is in the normal direction of the condensate plane, with the increasing of the strength of DDI, the visibility of fringes reduces and the width of fringes becomes larger. When the strength of DDI is fixed and the effective polarization direction of the dipolar atoms deviates from the normal direction of the condensate plane, the interference fringes become bent. Especially, for the situation of polarization parallel to the condensate plane, the interference fringes in the central regions become wave-shaped and vortex-antivortex pairs can be formed due to the anisotropic DDI. In addition, vortex-antivortex pairs could also be created by the spatial and temporal control of the DDI.